Early and late behavioral consequences of ethanol withdrawal: focus on brain indoleamine 2,3 dioxygenase activity.

Anxiety and depression are symptoms associated with ethanol withdrawal that lead individuals to relapse. In the kynurenine pathway, the enzyme indoleamine 2,3 dioxygenase (IDO) is responsible for the conversion of tryptophan to kynurenine, and dysregulation of this pathway has been associated with psychiatric disorders, such as anxiety and depression. The present study evaluated the early and late behavioral and biochemical effects of ethanol withdrawal in rats. Male Wistar rats were submitted to increasing concentrations of ethanol in drinking water during 21 days. In experiment 1, both control and withdrawal groups were submitted to a battery of behavioral tests 3, 5, 10, 19, and 21 days following ethanol removal. In experiment 2, animals were euthanized 3 days (short-term) or 21 days (long-term) after withdrawal, and the brains were dissected altogether, following kynurenine concentration analysis in prefrontal cortex, hippocampus, and striatum. Short-term ethanol withdrawal decreased the exploration of the open arms in the elevated plus-maze. In the forced swimming test, long-term ethanol-withdrawn rats displayed higher immobility time than control animals. Ethanol withdrawal altered neither locomotion nor motor coordination of rats. In experiment 2, kynurenine concentrations were increased in the prefrontal cortex after a long-term period of withdrawal. In conclusion, short-term ethanol withdrawal produced anxiety-like behaviors, while long-term withdrawal favored depressive-like behaviors. Long-term ethanol withdrawal elevated kynurenine levels, specifically in the prefrontal cortex, suggesting that the depressive-like responses observed after long-term withdrawal might be related to the increased IDO activity.

Carrion decomposition and assemblage of necrophagous dipterans associated with Terbufos (Organophosphate) intoxicated rat carcasses.

Organophosphate use represents one of the main causes of intentional and accidental poisoning in Brazil. Because they induce alteration in carcass decomposition and succession of necrophagous Diptera, they are important investigative tool in forensic entomology for determining the postmortem interval (PMI) and cause of death. Thus, this work aimed to evaluate the influence of Terbufos, the most commonly used organophosphate for suicides in Rio Grande do Norte, Brazil, in the decomposition process and necrophagous fly assemblies in intoxicated rat carcasses. For this, 150g female Wistar rats received, by gavage, 200µL of Terbufos (5mg/kg or 10mg/kg) or distilled water (control). Approximately 30 minutes after administration, animals were euthanized and distributed in suspended traps to decompose under environmental conditions. Decomposition was monitored daily, with photographic record and collection of the visiting dipterofauna until the dry phase. Data show that the higher dose of Terbufos i) accelerates carcass decomposition in 24h; ii) decreases the species richness and abundance of scavengers flies when compared to the control; iii) changes the succession pattern, delaying the arrival of important species for the PMI estimate and iv) causes 8% mortality of the visiting dipterofauna. This work provides relevant information about dipteran assemblages and changes in the cadaver decomposition process associated with Terbufos intoxication, which may assist in future investigative processes with suspected organophosphate poisoning.